Re: [Lilypond-auto] Issue 1450 in lilypond: Collision between slur and text in les-nereides regtest

[lilypond]

Comment #6 on issue 1450 by address@hidden: Collision between slur and  
text in les-nereides regtest
http://code.google.com/p/lilypond/issues/detail?id=1450

I have a plan of action that I think will fix this, but it'll take some  
time to implement.  I'll likely make this my next project.

For cross-staff spanners, create dummy grobs of the same type (beam, slur,  
etc.) for every time the grob switches contexts.  These grobs will have no  
width or height but will have stencils calculated based only on the notes  
in that context.  In Axis_group_interface::skyline_spacing, these grobs  
will be included in VerticalAxisGroups for the portion of the group over  
which the group is extremal and the spanner's direction is the same as this  
extremity.  This approximation will almost always be not-too-far from the  
actual and will avoid stuff like the les-nereides.ly collision.

Note that this whole mess would be avoided through some sorta linear  
program for the vertical layout of a page, which'd only need as variables  
the control points of the cross staff spanners and the Y offset of the  
systems on the page.  Everything else would be a constant.  So it'd be much  
more solvable by GLPK than the monstrosities I used to dream about where  
the entire spacing process was controlled through a single linear program.